Pteridium esculentum (G.Forst.) Cockayne

Terrestrial ferns. Rhizomes long-creeping, bearing multicellular hairs. Fronds 250–2000 mm long or more. Stipes 1–10 mm diameter, bearing petiolar roots distally above the junction with the rhizome. Rachises with swollen nectaries at the base of the primary pinnae. Laminae 2-pinnate-pinnatifid to 5-pinnate, broadly ovate or broadly elliptic, bearing hairs, lacking scales. Some lamina segments adnate at base with long-decurrent bases either extending along the axes, or often becoming separated as free lobes forming narrow wings. Ultimate lamina segments linear and entire; adaxial surface dark green and glossy; abaxial surface paler green, bearing white hairs and minute gnarled trichomes that create a farinaceous or mealy appearance. When fertile, sori almost continuous along margins of ultimate segments, protected by the inrolled lamina margin.

Pteridium esculentum is distinguished from the northern hemisphere diploid species, P. aquilinum, by the presence of petiolar roots at the base of the stipe above the junction with the rhizome, winged axes that appear as free lobes or as long-decurrent bases to the lamina segments (Thomson 2016), and gnarled trichomes on the abaxial lamina surface that cause a farinaceous or mealy appearance (Thomson 2012). These features are all absent in P. aquilinum.

Pteridium esculentum is a serious weed of pasture, aggressively invading cleared or burnt land and forming extensive populations by means of its underground rhizomes. It eventually disappears under regenerating scrub and forest. It is found in rough and reverting pasture, on road cuttings and banks, in ditches, on lake and forest margins, in peat bogs, on old sand dunes, on cliff faces, in forest clearings and disturbed ground, along river beds and terraces, in tussock land, and on heated ground. Although mostly found in the open, it also occurs under podocarp, broadleaved and beech forest, under mānuka and kānuka, in coastal and other scrub, and under pine plantations.

n = 52 (Brownlie 1954, 1957).

Thomson (2012) recognised two species of diploid bracken: the predominantly northern hemisphere Pteridium aquilinum (L.) Kuhn and the mainly southern hemisphere Pteridium esculentum. He further recognised 11 subspecies within P. aquilinum and two subspecies within P. esculentum – subsp. esculentum confined to Australia, New Zealand, New Caledonia, Solomon Islands, New Guinea, Vanuatu, Fiji and Tonga, and subsp. arachnoideum (Kaulf.) J.A.Thomson confined to Central and South America. However, Schwartsburd et al. (2014) continued to treat the South American plants as a distinct species, P. arachnoideum (Kaulf.) Maxon.